Sneeze Simulator Reveals the Spread of Unseen Germs

A 3D-printed model of the human nose and upper airway, capable of simulating coughing and sneezing, has given researchers valuable insights into the transmission of airborne infections. This information will support efforts to develop strategies for minimizing their spread.

The COVID-19 pandemic highlighted how quickly respiratory diseases can be transmitted through coughs and sneezes. While replicating airborne disease transmission is crucial for understanding its dynamics, relying on sick individuals for studies isn’t always feasible.

Innovative 3D Model Simulates Coughs and Sneezes to Study Infection Spread

Moreover, researchers at the Universitat Rovira i Virgili (URV) in Spain have developed a 3D model of the human nasal cavity and upper airway capable of simulating coughs and sneezes, providing a more detailed way to study the spread of infectious particles.

“This innovative experimental setup generates exhalations mimicking human coughs and sneezes, with adjustable parameters to control the strength of air ejection,” the researchers explained. “Using realistic 3D-printed models of the upper respiratory tract and nasal cavity, we can examine how exhalation strength and nasal airways (with or without nostril blockage) influence aerosol cloud dispersion.”

The Role of the Nasal Cavity in Disease Spread

The nasal cavity plays a key role in influencing airflow dynamics, as well as the size, direction, and dispersion of particles expelled during a cough or sneeze. Particles released through the nose differ from those expelled through the mouth, and these variations can affect how diseases spread. To account for these factors, the researchers aimed to create a highly realistic respiratory model.

Using high-speed cameras and laser beams, the team analyzed the real-time dispersion of airborne particles. They measured the trajectory and width of particle clouds under various experimental conditions designed to replicate different “violent expiratory events” through either the nose or mouth.

In fact, the researchers discovered that exhaling through the nose caused infectious particles to be deflected downward, resulting in more vertical and less horizontal dispersion. While this may lower the immediate risk of transmitting disease to nearby individuals, it also prolongs the suspension of particles in the air. In poorly ventilated, confined spaces, this can elevate the risk of long-term exposure.

A Greater Risk for Close-Contact Transmission

In contrast, exhaling through the mouth propelled infectious particles farther along a horizontal path. According to the researchers, this dispersal pattern increases the likelihood of infecting those nearby, as particles are more likely to directly land on individuals, particularly during face-to-face interactions or in shared spaces.

Insights into Indoor Particle Dispersion and Airborne Disease Spread

“These findings enhance our understanding of how particle nuclei disperse in indoor spaces and, in turn, how airborne diseases spread,” said Nicolás Catalán, lead author of the study and a researcher in URV’s Department of Mechanical Engineering.

Although more research is required to explore the impact of environmental factors like humidity and temperature on particle dispersion, the insights from this study can guide the development of effective ventilation strategies for settings such as restaurants, classrooms, hospitals, and public transportation.

“By optimizing ventilation systems based on particle cloud dynamics, we can significantly reduce the risk of airborne disease transmission,” the researchers noted.

Read the original article on: New Atlas

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